Mont Saint-Michel was used in the sixth and seventh centuries as an Armorican stronghold of Gallo-Roman culture and power until it was ransacked by the Franks, thus ending the trans-channel culture that had stood since the departure of the Romans in CE 460. From roughly the fifth to the eighth century, Mont Saint-Michel belonged to the territory of Neustria, and in the early ninth century was an important place in the marches of Neustria.